ASTEROIDEA 8i 



variation in Odontaster, I am strongly inclined to follow a middle course and to leave 

 these four species in Leptychaster, to which I would add Trophodisciis . In order to 

 emphasize what seem to be valid sections I would institute subgenera based upon 

 anatomical characters, the value of which must be determined by experience. 



Genus Leptychaster Smith 



Subgenus Leptychaster. Type L. kerguelenetisis. Form stellate ; adambulacrals short, 

 with very angular furrow margin ; gonads of both sexes in several to many tufts extend- 

 ing along dorsal wall of ray ; marginal mouth spines forming a decurrent angle near 

 inner end of plates. 



fli. Papulae confined to rather narrow marginal area, where plates have short lobes; elsewhere 



roundish. 

 b^. Series of gonads near margin of abactinal area; paedophoric. L. kerguelenetisis Smith. 



¥•. Series of gonads well spaced from margin: rays very long; probably not paedophoric. 



L. flexiiosiis Koehler. 

 a-. Papulae distributed all over abactinal surface; all abactinal plates, except in young of 



accrescens, strongly lobed; species probably not paedophoric. L. magnificiis (Koehler). 



L. accrescens Koehler. 



Subgenus Porastropecten Ludwig. Type P. inermis Ludwig {Glyphaster Verrill, type 

 Leptychaster anomalus Fisher). Form stellate to arcuate stellato-pentagonal ; adambula- 

 cral plates with rounded furrow margin bearing a comb of 3-6 spines ; gonads of male in 

 a series, those of female in a strictly interradial tuft ; abactinal plates lobed except for 

 rather narrow radial area free from papulae; marginal mouth spines not forming an 

 evident decurrent angle near inner end of plate ; probably not paedophoric. 

 L. inermis Ludwig.^ 

 L. anomalus Fisher. 

 L. propinquus Fisher. 

 L. pacificus Fisher. 

 L. arcticus (Sars). 



Subgenus Trophodisciis Fisher. Type T. almus Fisher (19170, p. S^?' P^s- 28-30). 

 Stellate-pentagonal; marginal plates conspicuous, granular; adambulacral armature 

 pectinate ; first adambulacral plate compressed ; both male and female gonads serially 

 arranged ; abactinal plates of papular area with short lobes ; papulae absent from centre 

 of disk and narrow midradial band ; marginal mouth spines not forming a decurrent 

 angle. 



L. almus Fisher. 



In the diagnosis of Trophodiscus {loc. cit.) is the following: "Near to Leptychaster 

 Smith, but differing in having both ovaries and testes serially arranged along each side of 

 the proximal half of ray." This error is due to the circumstance that comparison was 

 made with L. anomalus, L. pacificus and L. arcticus, in which the ovaries are interradial 



1 The type is immature. The species greatly resembles L. anomalus. If it happens that the gonads are 

 different from those of anomalus, then Glyphaster will be available for anomalus, propinquus and arcticus. 



